The use of data flow control in communication networks is known and many solutions, for example transmission control protocol and internet protocol (TCP/IP) and IEEE 802.3, have been identified for different layers in the network stack. These historic solutions work well when the network is homogenous (i.e. roughly the same network speed on all links), duplex (i.e. data is sent in both directions), and where the delay between sending and receiving is manageable. In addition, the historic solutions work well when all devices in an area of data congestion can identify and report overloads, and report the overload to its immediate neighbor in the network link.
In the case of satellite communications, a typical communication network cannot fully maximize IP traffic over a satellite because the network is unable to detect how fast data is transmitted. Therefore, data transfer is regulated based upon link estimates. The result is much less data is sent than is theoretically possible across an IP satellite link.
For military avionics systems using IP over satellite, there is no support for flow control between a router and the modem sending the data packets to the satellite from the aircraft. There is also typically an encryption device or other security device between the router and the modem which prevents flow control from the modem, if the modem even supports flow control, from reaching the router. The router will take data as fast as an application generates it, and route the data packets to the modem. However, the modem will drop the packet if the modem is overloaded thereby causing data loss.
A lost data packet is lost forever if it is part of real-time streamed video. In certain circumstances, that lost packet can contain critical data, such as a clear picture of the enemy or a friendly. It may be a very long time before the system can retransmit the video and guarantee it is intact and correct.
Improvements in communication systems to maximize data transmission and prevent loss of data are needed.